The present invention relates to a nonwoven web of a distinct design which has been specially treated with a fluorocarbon or other repellent agent and then top-coated with a polymer coating which essentially coats the top of the nonwoven web to form a fluid impervious barrier without saturating the nonwoven web or batt.
Latex-saturated webs are well known. Nonwoven materials are frequently run through coating solutions such as in a dip-and-squeeze method and then allowed to dry, thereby forming a saturated nonwoven web which may have varying degrees of impermeability to liquids and gasses. While such saturation techniques are well suited for a number of end uses, they do in fact utilize a large amount of the saturant. This is particularly true if fluid barrier properties are only needed on one side of the nonwoven web. As a result, it is an object of the present invention to provide a nonwoven web which has a uniform coating on one surface of the nonwoven web, thereby reducing the amount of saturant or coating material needed to create a material which is fluid-impervious.
While there are a wide variety of nonwovens, many of which can be completely saturated, there are currently only a select few nonwoven materials that can be surface coated with a fluid-impervious layer such as latex. One example can be found in U.S. Pat. No. 4,818,600, which is commonly assigned to the assignee of record. This patent teaches the use of a coating of a polyacrylate (latex) on one surface of a microfibrous meltblown nonwoven web. Surface coating of this material is possible because of the fine fiber structure and small pore size of the meltblown material. These features of the nonwoven permit the coating to treat the surface and not substantially soak into the material as the fluid impervious polyacrylate layer is formed. A problem arises, however, when the surface coating of a larger fiber, more porous material such as a spunbond nonwoven is attempted. More often than not, spunbond materials have much larger fibers and larger pores than microfibrous meltblown materials. As a result, the same types of coatings that are used to coat meltblown nonwovens cannot always be used to surface coat spunbond or other larger fiber structures. This is because the coatings cannot bridge the gaps between the fibers; therefore, the coating penetrates into the interior regions of the nonwovens. Accordingly, it is another object of the present invention to provide a nonwoven structure utilizing larger fibers which can still be surface coated with a fluid-barrier coating such as latex. It is also an object of the present invention to provide a process for producing such materials. These and other objects of the present invention will become more apparent upon a further review of the following specification, drawings and claims.